That's tough and it may not even be the truth.
I had a bestfriend from when we were toddlers until I was in Grade 5 (he was a year older). My friend started to not want to hang out because he was going through puberty and just wanted to eat instead of 'play'. And, unfortunately I started to bully him and make fun of him at school because of it. My mom asked me one time why we didn't play anymore and I just told her he was smoking and hanging out with bad kids to stop her from asking. The thought process of a kid being that if it's something I know my mom doesn't want me doing she will be happy I'm not hanging around him.
Kids can change over time and even they don't always understand it. The key is to really listen when they talk to understand what they are getting at. And, if this is the truth from your kid's perspective he's going to be dealing with a bunch of emotions he doesn't understand. From envy of his friend having a girl to anger and frustration of losing a best-friend to loneliness as now he has to fill the hole of a best-friend with something else.
This book really helps give you a better perspective when talking with teenagers.
I don't remember if it tackles exactly what you mentioned but I've enjoyed reading How to Talk So Teens Will Listen and Listen So Teens Will Talk even though I'm not a parent (I was on a nonviolent communication tear) and thought it contained great communication advice
I bet she really wishes you could go back to the way things were before as well. But, she realizes that she's the only person around to parent you now, and that's a big responsibility. Imagine if you had a 12-year-old sister who you suddenly became responsible for and think of all the changes between 12 and 16 that you'd need to help her navigate, and how you'd want to help her get through those years as physically, mentally, and emotionally healthy as possible because you'd love her. Ages 16 to 24 are even more critical and intense than that and she wants what's best for you.
It turns out no one teaches you how to be a parent, even when you give birth to your own kids. A lot of us just do the best we can, but spend a lot of time failing and flailing. I've got my shit pretty well together as adults go, and I sometimes still feel like I have absolutely no idea what the "right" thing to do to best guide my kids through to adulthood. Your sister at 24 suddenly trying to live up to this responsibility must feel incredibly underprepared. We're all just making it up as we go along.
All that said is not by any means to discount your feelings. This is hard all around. Do you have access to a therapist at all who you can talk this through with? It's a lot to ask of you, but I think if you'd able to get in a calm headspace and sit down with her and try to empathize with each other, it'd go a long way. Try asking her what she's concerned about and what her goals are in her caring for you. Is she worried about you being injured by alcohol or drug use? Concerned about driving safety? Worried about you being in situations with a higher risk of sexual violence? Worried about ensuring your academic success so you can go on to successful higher education and career?
It's not fair to you in the grand scheme of the universe that you need to be involved in your own parenting, but we don't always get a choice. Once you together have an understanding of what risks you are trying to avoid and what goals you are trying to reach, you can talk about finding a collaborative approach. What will help her be comfortable with you having independence and privileges and what consequences make sense for potential errors. That said, being 16 is about making mistakes. Maybe ask her to share more about what her high school years were like and what is reasonable risk-taking and what's too much.
This may be a little far out there, but you could do worse that to both read How to Talk So Teens with Listen and Listen so Teens Will Talk (https://www.amazon.com/dp/B003V1WW2O/). She could probably use some advice, and that's a good one. And if you're able to proactively engage with her, it may help you feel more empowered in the relationship. If she feels like you're taking more responsibility for your own behavior, she may feel like it's less necessary for her to be "in charge" all the time.
Maybe you could even set aside some regular time in the week/month that you specifically do a "sister date" of sorts where you do something normal and fun for both of you where you don't have to think about the parenting dynamic.
Like I said, we're all just making it up as we go along, so I'm not sure if any of this advice will be helpful or correct. The fact you're reaching out for advice though is great. I hope you and your sister can find a way to work together to improve the situation for both of you.
It's the sole purpose of teenagers to rebel.
I like this author, haven't read this exact book though.